Presentation 18 of parathyroid glands surgery

Presenting about parathyroid glands and function and anatomy and surgery

1. Parathyroid glands

2. Overview These glands, located behind the thyroid at the bottom of a neck, are about the size of a grain of rice. The parathyroid hormone produced by the thyroid glands helps maintain the right balance of calcium in the bloodstream and in tissues that depend on calcium for proper functioning. This is especially important for nerve and muscle function, as well as bone health.

3. Normally, this balancing act works well When calcium levels in blood fall too low, parathyroid glands release enough parathyroid hormone to restore the balance. This hormone raises calcium levels by releasing calcium from bones, increasing the amount of calcium absorbed from small intestine and decreasing the amount of calcium lost in urine. When blood-calcium levels are too high,  the parathyroid glands produce less parathyroid hormone.

4. Hyperparathyroidism Hyperparathyroidism is when a parathyroid glands create high amounts of parathyroid hormone in the bloodstream.

5. Hyperparathyroidism There are two types of hyperparathyroidism: Primary hyperparathyroidism Secondary hyperparathyroidism

6. Primary hyperparathyroidism Primary hyperparathyroidism occurs because of a problem with one or more of the four parathyroid glands: A noncancerous growth (adenoma) on a gland is the most common cause. Enlargement (hyperplasia) of two or more parathyroid glands accounts for most other cases. A cancerous tumor is a very rare cause of primary hyperparathyroidism One or more of the parathyroid glands produces high amounts of parathyroid hormone. This leads to high calcium levels and low phosphorus levels in blood

7. Secondary hyperparathyroidism Development of secondary hyperparathyroidism is the result of several other conditions that lower Ca+ levels, which then affects the gland's function: Severe calcium deficiency = b ody may not get enough calcium from diet, often because digestive system doesn't absorb the calcium from food Severe vitamin D deficiency = body produces vitamin D when skin is exposed to the sunlight and vitamin rich food. Chronic kidney failure = K idneys convert vitamin D into a form that body can use. If kidneys work poorly, usable vitamin D may decrease and calcium levels drop. This causes parathyroid hormone levels to go up. Chronic kidney failure is the most common cause of secondary hyperparathyroidism

8. Symptoms Weak bones that break easily (osteoporosis) Kidney stones Oliguria Stomach (abdominal) pain Fatigue or weakness Depression or forgetfulness Bone and joint pain Frequent complaints of illness with no clear cause Nausea, vomiting or loss of appetite

9. Secondary hyperparathyroidism

10. Hypoparathyroidism Hypoparathyroidism is a deficiency of parathyroid hormone often caused by an autoimmune disorder or by iatrogenic damage or removal of the glands during thyroidectomy or parathyroidectomy. Symptoms of hypoparathyroidism are due to hypocalcemia and include tingling in the hands or around the mouth and muscle cramps. In severe cases, tetany occurs.

11. Postoperative hypoparathyroidism Transient hypoparathyroidism is common after thyroidectomy, but permanent hypoparathyroidism occurs after < 3% of such thyroidectomies done by experienced surgeons. Manifestations of hypocalcemia usually begin about 24 to 48 hours postoperatively but may occur after months or years. PTH deficiency is more common after radical thyroidectomy for cancer or as the result of surgery on the parathyroid glands (subtotal or total parathyroidectomy).

12. The thyroid gland The thyroid gland, located in the anterior neck just below the cricoid cartilage, consists of 2 lobes connected by an isthmus. Follicular cells in the gland produce the 2 main thyroid hormones Tetraiodothyronine (thyroxine, T4) Triiodothyronine (T3) Thyroid hormone is required for normal brain and somatic tissue development in the fetus and neonate, and, in people of all ages, regulates protein, carbohydrate, and fat metabolism.

13. Hyperthyroidism Hyperthyroidism is characterized by hypermetabolism and elevated serum levels of free thyroid hormones. Symptoms include palpitations, fatigue, weight loss, heat intolerance, anxiety, and tremor The  most common causes  overall include Graves disease Multinodular goiter Thyroiditis Single, autonomous, hyperfunctioning "hot" nodule

14. Treatment of Hyperthyroidism Surgery is indicated for patients with Graves disease whose hyperthyroidism has recurred after courses of antithyroid drugs and who refuse iodine-131 therapy, patients who cannot tolerate antithyroid drugs, patients with very large goiters, and in some younger patients with toxic adenoma and multinodular goiter. Surgery may be done in older patients with giant nodular goiters.

15. Subacute Thyroiditis Subacute thyroiditis is an acute inflammatory disease of the thyroid probably caused by a virus. Symptoms include fever and thyroid tenderness. Initial hyperthyroidism is common, sometimes followed by a transient period of hypothyroidism. Diagnosis is clinical and with thyroid function tests. Treatment is with high doses of nonsteroidal anti-inflammatory drugs or with corticosteroids. The disease usually resolves spontaneously within months.

16. Silent Lymphocytic Thyroiditis Silent lymphocytic thyroiditis is a self-limited, subacute disorder occurring most commonly in women during the postpartum period. Symptoms are initially of hyperthyroidism, then hypothyroidism, and then generally recovery to the euthyroid state. Treatment of the hyperthyroid phase is with a beta-blocker. If hypothyroidism is permanent, lifelong thyroxine supplementation is needed.

17. Hypothyroidism (Myxedema) Hypothyroidism is thyroid hormone deficiency. Symptoms include cold intolerance, fatigue, and weight gain. Signs may include a typical facial appearance, hoarse slow speech, and dry skin. Diagnosis is with thyroid function tests. Management includes administration of thyroxine

18. Hashimoto Thyroiditis Hashimoto thyroiditis is chronic autoimmune inflammation of the thyroid with lymphocytic infiltration. Findings include painless thyroid enlargement and symptoms of hypothyroidism. Diagnosis involves demonstration of high titers of thyroid peroxidase antibodies. Lifelong levothyroxine replacement is typically required for patients who develop hypothyroidism

19. Approach to the Patient With a Thyroid Nodule Thyroid nodules are benign or malignant growths within the thyroid gland. They are common, increasingly so with increasing age

20. Etiology Most nodules are benign. Benign causes include  Hyperplastic colloid goiter  Thyroid cysts Thyroiditis Thyroid adenomas

21. Evaluation of a Thyroid Nodule Thyroid nodules may be painful or asymptomatic. Pain suggests thyroiditis or hemorrhage into a cyst. An asymptomatic nodule may be malignant but is usually benign Risk factors for thyroid cancer include History of thyroid irradiation, especially in infancy or childhood Age < 20 years Male sex Family history of  thyroid cancer  or  multiple endocrine neoplasia type 2 A solitary nodule Dysphagia Dysphonia Increasing size (particularly rapid growth or growth while receiving thyroid suppression treatment)

22. Physical examination Signs that suggest thyroid cancer include stony, hard consistency or fixation to surrounding structures, cervical lymphadenopathy, and hoarseness (due to recurrent laryngeal nerve paralysis).

23. Testing Initial evaluation of a thyroid nodule consists of  testing for Thyroid-stimulating hormone (TSH) Antithyroid peroxidase antibodies If thyroid function tests do not indicate  hyperthyroidism  or  Hashimoto thyroiditis , the next step is to examine the nodule with a thyroid ultrasound.

24. Testing Ultrasonography is useful in determining the size of the nodule, but may not allow a distinction between a benign or malignant lesion. Thyroid cancer is suggested by nodule hypoechogenicity ; marked internal vascularity; irregular borders; height of the nodule being greater than the width; irregular macrocalcifications; fine, stippled psammomatous microcalcifications (papillary thyroid carcinoma); or dense, homogenous irregular calcification (medullary thyroid carcinoma). 

25. Testing For nodules with suspicious features, fine-needle aspiration biopsy (FNAB) done under ultrasound guidance is the procedure of choice and the most economical means to distinguish benign from malignant nodules. FNAB is generally not recommended for nodules <1 cm or for nodules that are entirely cystic

26. Treatment of a Thyroid Nodule Treatment is directed at the underlying disorder. Nodules in patients with Hashimoto thyroiditis or other causes of goiter associated with hypothyroidism may stabilize or shrink with thyroxine replacement in doses that render the patient euthyroid. For small benign nodules not associated with hypothyroidism, thyroxine suppression of TSH effectively shrinks the nodule in no more than half the cases, and is seldom done.

27. Treatment of a Thyroid Nodule Large benign nodules that compress the surrounding neck structures may become smaller following radiofrequency ablation. Partial or complete thyroidectomy are effective for treating nodules that continue to grow or cause compressive symptoms.  Toxic nodules may be treated with radioactive iodine to control hyperthyroidism and reduce nodule size.

28. Treatment of a Thyroid Nodule Nodules that are not due to thyroid cancer, are not causing compressive symptoms and are not associated with either hypothyroidism or hyperthyroidism may be safely followed by periodic neck examination and, if there is suspicion of nodule growth, by repeat ultrasound evaluation.

29. Simple Nontoxic Goiter Simple nontoxic goiter, which may be diffuse or nodular, is noncancerous hypertrophy of the thyroid without hyperthyroidism, hypothyroidism, or inflammation. Except in severe iodine deficiency, thyroid function is normal and patients are asymptomatic except for an obviously enlarged, nontender thyroid. Diagnosis is clinical and with determination of normal thyroid function. Treatment is directed at the cause, but partial surgical removal may be required for very large goiters.

30. Thyroid Cancers There are 4 general types of thyroid cancer. Most thyroid cancers manifest as asymptomatic nodules. Rarely, lymph node, lung, or bone metastases cause the presenting symptoms of small thyroid cancers. Diagnosis is often by fine-needle aspiration biopsy but may involve other tests. Treatment is surgical removal, usually followed by ablation of residual tissue with radioactive iodine.

31. Papillary Thyroid Carcinoma Papillary carcinoma accounts for 80 to 90% of all thyroid cancers. The female:male ratio is 3:1. It may be familial in up to 5% of patients. Most patients present between ages 30 and 60. The tumor is often more aggressive in older patients. The tumor spreads via lymphatics to regional lymph nodes in one third of patients and may metastasize to the lungs. Patients < 55 years with small tumors confined to the thyroid have an excellent prognosis.

32. Papillary Thyroid Carcinoma Tumors > 4 cm or that are diffusely spreading require total or near-total thyroidectomy with postoperative radioiodine ablation of residual thyroid tissue with appropriately large doses of iodine-131 administered when the patient is hypothyroid or after recombinant thyroid-stimulating hormone (TSH) injections. Treatment may be repeated after 6 to 12 months to ablate any remaining thyroid tissue.

33. Papillary Thyroid Carcinoma

34. Follicular Thyroid Carcinoma Follicular carcinoma, including the Hürthle cell variant, accounts for about 10% of thyroid cancers. It is more common among older patients and in regions of iodine deficiency. It is more malignant than  papillary carcinoma , spreading hematogenously with distant metastases. Treatment requires near-total thyroidectomy with postoperative radioiodine ablation of residual thyroid tissue as in treatment for papillary carcinoma. Metastases are more responsive to radioiodine therapy than are those of papillary carcinoma. 

35. Medullary Thyroid Carcinoma Medullary carcinoma constitutes about 4% of thyroid cancers and is composed of parafollicular cells (C cells) that produce calcitonin. It may be sporadic (usually unilateral); however, it is often familial, caused by a mutation of the  ret  proto-oncogene. Metastases spread is via the lymphatic system to cervical and mediastinal nodes and sometimes to liver, lungs, and bone.

36. Medullary Thyroid Carcinoma All patients with medullary thyroid carcinoma should have genetic testing for mutations of the ret proto-oncogene; relatives of those with mutations should have genetic testing and measurement of basal and stimulated calcitonin levels. Total thyroidectomy is indicated even if bilateral involvement is not obvious. Lymph nodes are also dissected. If hyperparathyroidism is present, removal of hyperplastic or adenomatous parathyroids is required. Long-term survival is common in patients with medullary carcinoma and MEN 2A; more than two thirds of affected patients are alive at 10 years.

37. Anaplastic Thyroid Carcinoma Anaplastic carcinoma is an undifferentiated cancer that accounts for about 1% of thyroid cancers. It occurs mostly in older patients and slightly more often in women. The tumor is characterized by rapid, painful enlargement. Rapid enlargement of the thyroid may also suggest thyroid lymphoma, particularly if found in association with  Hashimoto thyroiditis .

38. Anaplastic Thyroid Carcinoma No effective therapy exists, and the disease is generally fatal. About 80% of patients die within 1 year of diagnosis. In a few patients with smaller tumors, thyroidectomy followed by external beam radiation therapy has been curative. Chemotherapy is mainly experimental. Up to 40% of these tumors harbor a  BRAF  V600E mutation. Targeted therapy with a combination of dabrafenib and trametinib has been shown to reduce tumor progression but has yet to been shown to improve long-term survival

39. Diabetes mellitus  Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high .

40. Diabetes mellitus  Urination and thirst are increased, and people may lose weight even if they are not trying to. Diabetes damages the nerves and causes problems with the sense of touch. Diabetes damages blood vessels and increases the risk of heart attack, stroke, chronic kidney disease, and vision loss.

41. Type 1 diabetes In type 1 diabetes (formerly called insulin-dependent diabetes or juvenile-onset diabetes), the body's immune system attacks the insulin-producing cells of the pancreas, and more than 90% of them are permanently destroyed. The pancreas, therefore, produces little or no insulin. Only about 5 to 10% of all people with diabetes have type 1 disease. 

42. Type 2 diabetes In type 2 diabetes (formerly called non–insulin-dependent diabetes or adult-onset diabetes), the pancreas often continues to produce insulin, sometimes even at higher-than-normal levels, especially early in the disease. However, the body develops resistance to the effects of insulin, so there is not enough insulin to meet the body’s needs. As type 2 diabetes progresses, the insulin-producing ability of the pancreas decreases.

43. Complications of Diabetes Mellitus People with diabetes mellitus have many serious long-term complications that affect many areas of the body.

44. Complications of Diabetes Mellitus Blood vessel complications Infectious problems Eye problems Liver damage Kidney damage Nerve damage Foot problems

45. Foot problems in diabetes Diabetes causes many changes in the body. The following changes in the feet are common and difficult to treat

46. Foot problems in diabetes Damage to the nerves (neuropathy) affects sensation to the feet, so that pain is not felt. Irritation and other forms of injury may go unnoticed. An injury may wear through the skin before any pain is felt. Changes in sensation alter the way people with diabetes carry weight on their feet, concentrating weight in certain areas so that calluses form. Calluses (and dry skin) increase the risk of skin breakdown. Diabetes can cause poor circulation in the feet, making ulcers more likely to form when the skin is damaged and making the ulcers slower to heal.

47. Foot problems

48. Foot Ulcer